Copper-catalyzed oxidative cross-dehydrogenative coupling of 2<i>H</i>-chromenes and terminal alkynes
作者:Fei Yang、Yangshan Li、Paul E. Floreancig、Xiaoyan Li、Lei Liu
DOI:10.1039/c8ob00949j
日期:——
An efficient copper-catalyzedcross-dehydrogenativecoupling of 2H-chromenes and terminal alkynes mediated by DDQ has been established. A protic additive, EtOH, proved to be crucial for harmonizing the oxidation with a subsequent alkynylation step by retaining the oxidation state of an oxocarbenium ion in the form of acetal. The CDC reaction exhibits a good substrate scope, with a range of terminal
Catalytic Asymmetric Addition of Aldehydes to Oxocarbenium Ions: A Dual Catalytic System for the Synthesis of Chromenes
作者:Magnus Rueping、Chandra M. R. Volla、Iuliana Atodiresei
DOI:10.1021/ol302084q
日期:2012.9.7
A synergistic catalytic system for the first asymmetric addition of aldehydes to in situ generated prochiral oxocarbenium ions has been developed. The dual catalytic protocol allows the simultaneous activation of both electrophile and nucleophile and provides access to a variety of valuable chiral 2H-chromenes with excellent enantioselectivities.